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 Post subject: Cartridge type for Newcomb TR1656M?
PostPosted: Feb Sat 10, 2018 6:59 am 
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Working on a Newcomb TR1656M phonograph / PA system. Looks like the cartridge was previously replaced, and it appears to have far too high output for this unit.

Equalization from the phono input is rather bassy - almost like what one might expect for a magnetic cartridge.

I'd be surprised if a magnetic cartridge was used in this rather "industrial" phonograph from 1960. Does anyone have an idea what kind of cartridge this was intended for? Some kind of low output ceramic cartridge?

The label says it needs a "Recoton 470-D" cartridge. Or maybe that's the needle?

Searching on the website for V-M Audio, I see they show this one as a possibility for Newcomb. The turnaround needle seems right, since there is a hole in the top of the tone arm. And it's magnetic. Maybe the right one for this unit?

http://www.thevoiceofmusic.com/catalog/ ... ategories=

Image

Only $72 to buy one... (!)

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 Post subject: Re: Cartridge type for Newcomb TR1656M?
PostPosted: Feb Sat 10, 2018 4:00 pm 
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Recoton 470-D is indeed Recoton's number for the styli for the GE VRII magnetic cartridge. Because these cartridges generally don't got bad, and the only rubber involved is part of the replaceable needle, perhaps you could dig up a used VRII cartridge somewhere.


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 Post subject: Re: Cartridge type for Newcomb TR1656M?
PostPosted: Feb Sat 10, 2018 6:58 pm 
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Thanks for confirming, Ken. I'll see if the guy who owns this wants to buy the correct cartridge. He might, since this is overall a pretty high quality unit with a hefty audio amplifier.

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 Post subject: Re: Cartridge type for Newcomb TR1656M?
PostPosted: Feb Sat 10, 2018 11:54 pm 
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The M suffix indicates magnetic cartridge. I have a TR-1625M -- I'm using a Shure M35X cartridge tracking at 3 grams, strapped for mono. This way I can play stereo records. I also have a Shure 3 mil stylus to play 78s.

-David


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 Post subject: Re: Cartridge type for Newcomb TR1656M?
PostPosted: Feb Sun 11, 2018 4:49 am 
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Looking at output data, it looks like the GE VRII has considerably higher output (12 mV) than modern magnetic cartridges. Is the output level of the Shure sufficient for the Newcomb?

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 Post subject: Re: Cartridge type for Newcomb TR1656M?
PostPosted: Feb Sun 11, 2018 8:25 pm 
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I believe GE specified its magnetic cartridges at a higher velocity than is used today, so in fact the RPX and VR II outputs are very similar to today's cartridges. In any event, the TR-1625M has plenty of gain for the Shure cartridge. The preamp is very conventional, both halves of a 12AX7, so should work with any modern moving magnet cartridge. The only change I made was to replace the 100k load resistor with 47k.

-David


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 Post subject: Re: Cartridge type for Newcomb TR1656M?
PostPosted: Feb Sun 11, 2018 9:23 pm 
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dberman51 wrote:
The only change I made was to replace the 100k load resistor with 47k.

-David


Ah, the devl is in the details. Thanks for that tip.


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 Post subject: Re: Cartridge type for Newcomb TR1656M?
PostPosted: Feb Mon 12, 2018 7:14 am 
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David, is there a concern that the mono cartridge may lack enough vertical compliance to allow for the vertical motion in a stereo-recorded groove? I would think most mono cartridges have enough compliance in all directions that they should be OK, but I'm curious about your comment regarding being able to play stereo records better with the stereo cartridge.

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 Post subject: Re: Cartridge type for Newcomb TR1656M?
PostPosted: Feb Mon 12, 2018 6:09 pm 
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If you look at the stylus of a GE VRII cartridge, the cantilever sits on a rubber block. This lets the stylus travel back and forth freely, but it really can't move up and down much.


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 Post subject: Re: Cartridge type for Newcomb TR1656M?
PostPosted: Feb Mon 12, 2018 6:15 pm 
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Very interesting! Thanks.

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